e76defbcf0
The existing format of pg_dependencies uses a single-object JSON
structure, with each key value embedding all the knowledge about the
set attributes tracked, like:
{"1 => 5": 1.000000, "5 => 1": 0.423130}
While this is a very compact format, it is confusing to read and it is
difficult to manipulate the values within the object, particularly when
tracking multiple attributes.
The new output format introduced in this commit is a JSON array of
objects, with:
- A key named "degree", with a float value.
- A key named "attributes", with an array of attribute numbers.
- A key named "dependency", with an attribute number.
The values use the same underlying type as previously when printed, with
a new output format that shows now as follows:
[{"degree": 1.000000, "attributes": [1], "dependency": 5},
{"degree": 0.423130, "attributes": [5], "dependency": 1}]
This new format will become handy for a follow-up set of changes, so as
it becomes possible to inject extended statistics rather than require an
ANALYZE, like in a dump/restore sequence or after pg_upgrade on a new
cluster.
This format has been suggested by Tomas Vondra. The key names are
defined in the header introduced by
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| configure | ||
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| COPYRIGHT | ||
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| HISTORY | ||
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| README.md | ||
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.